Reactants:Fig. 10-46 COProducts:12 H O6 O6 HOCHOIn cellular respiration, glucose is converted to CO2 and water by transferring electrons to O2 thereby releasing lots of energy. In photosynthesis, electrons are stripped off of water and transferred to CO2 to reduce carbon to the carbohydrate level. This process requires lots of energy and releases O2as a byproduct.